Spring structure



IJuly 28,1942. T. DJSTE'WTTTTT TT TTL 2,291,004`

SPRING STMJCTURE Filed July ge, 1940 Patented July 28, 1942 SPRING STRUCTURE Theodore D. Stewart and William A. Clark, De-

troit, Mich., assignors to L. A. Young Spring and Wire Corporation, Detroit, Mich., a corporation of Michigan Application July 26, 1940, Serial No. 347,630

6 Claims.

This invention relates to improvements in spring structures.

The main objects of this invention are:

First, to provide an improved spring structure which is well adapted as a supporting means for superimposed springs or upholstery padding.

Second, to provide a structure having these advantages which is well adapted for use in a back structure for coupes and the like where the maximum of knee room is desired for a rear seat and a, minimum of bulk in the back of the cushion and at the same time the structure has the desired resiliency.

Third, to provide in a spring structure an improved bowed spring unit which has the desired resiliency and is of balanced character and resistant to lateral distortion.

Fourth, to provide a bowed spring unit which has the desired resilience and at the same time is readily mounted and when mounted is-effective against lateral or canting distortions.

Objects relating to details and economies of the invention will appear from the description to follow. The invention is defined and pointed out in the claims.

Preferred embodiments of the invention are illustrated in the accompanying drawing, in which:

Fig. 1 is a fragmentary plan view of a, spring structure embodying the features of our invention, the structure illustrated being primarily designed as a back spring for automobile seats, the upholstering being shown conventionally.

Fig. 2 is a vertical section on a line corresponding to line 2 2 of Fig. 1, the pocketed springs being indicated in full lines.

Fig. 3 is a side elevation of one of the units shown by full lines in its relaxed position and in its extended or mounted position by dotted lines.

Fig. 4 is a fragmentary plan view showing the position of the end arms of the end loops when in their relaxed position.

Fig. 5 is a fragmentary section corresponding to that of Fig. 2 showing the upholstery padding supported directly upon the spring members, the pocketed cushion springs of Fig. 2 being omitted.

In the embodiment of our invention illustrated, the border frame I is formed of suitable rod stock as a. continuous frame, its side members 2 having offsets 3 therein for locating the spring unit attaching clips 4.

The spring units 5 are each formed of a pair of strands designated by the numerals 6, 6, these strands being 'of spring wire and having loops 'I of substantial length formed therein, the loops of the strands being arranged in opposed relation, the reaches l of the strands between the loops being twisted together.

The endarms l of the end loops of the units are in relaxed position substantially separated as shown in Fig. 4. These arms 9 terminate in lugs I0 which are engaged by the clips 4, the arms being compressed to bring these lugs into abutting engagement to receive the clips. The clips clamp the endsof the spring units to the opposite members 2 of the frame.

It will be understood that the supporting members to which the ends may be secured may be greatly varied in size and shape of structure. As a matter of fact, they would vary according to the particular character of spring structure desired. The structure illustrated in which the border frame is formed of wire stock is, as stated, well adapted for use in a back cushion structure. The spring units are given a normal set or bow as indicated in Fig. 3, the arc of this initial set being of substantially less radius than the arc when the spring units are mounted on their support as is indicated by dotted lines in Fig. 3.

In the structure illustrated in Figs. 1 and 2, the pocketed springs designated generally by the numeral I I are arranged on the spring units, the upholstery padding I2 being supported by these pocketed springs and the upholstery covering I3 suitably secured to the frame. When the structure is used as a back structure in a coupe, for example, the forward bowing of the springs adds substantially to the knee space for the rear seat.

In the embodiment shown in Fig. 5, the upholstery padding Il is supported directly upon the spring unitsthat is, the fabric I5 of the padding is disposed directly thereon.

'I'he spring units may be formed for the desired resiliency and at the same time they are very resistant to lateral distortion or twisting which is one objection to certain of the types of bowed springs, particularly the zig-zag type.

While we have mentioned automobile back and seat cushions, it will be understood that our invention has a wide range of uses-for example, in household furniture, busses, railway cars, and the like.

We have illustrated and described our invention in an embodiment which we have found highly satisfactory. We have not attempted to illustrate or describe certain embodiments or adaptations which we contemplate as it is believed that this disclosure will enable those skilled in the art to embody or adapt our improvements as may be desired.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent, is:

1. In a spring structure, the combination with a border frame, of a plurality of bowed compression spring units disposed in spaced parallel relation relative to each other, each unit comprising strands of spring wire having longitudinally spaced loops of substantial length disposed with the loops of the strands in opposed oppositely disposed relation, the reaches of the strands between the loops being rigidly secured together, the outer arms of the end loops ofthe strands being secured to opposite sides of said border frame with the spring units in bowed position and on an arc of substantially greater radius than the radius of the unit when it is relaxed, the end arms of the end loops being substantially spaced when relaxed and being secured to the frame in compressed position whereby to tension the end loops.

2. In a spring structure, the combination with opposed supporting` members, of a plurality of bowed spring units disposed in spaced parallel relation relative to each other, each unit comprising strands of spring wire having longitudinally spaced loops of substantial length disposed with the loops of the strands in opposed oppositely disposed relation, the reaches of the strands between the loops being connected, the outer arms of the end loops of the strands being secured to said supporting members with the spring units in bowed position and on an arc of substantially greater radius than the radius of the unit when it is relaxed, the end arms of the end loops being substantially spaced when relaxed and being secured to the frame in compressed position whereby to tension the end loops.

3. A bowed spring unit comprising a frame and strands of spring wire having spaced oppositely disposed loops therein of substantial length, said strands being twisted together between the loops for action as a unit, the terminal arms of the end loops being parallel to one another and substantially spaced in normal relaxed position and being deiiected toward one another and attached to said frame whereby to tension said end loops.

4. A spring unit comprising strands of spring wire having longitudinally spaced loops therein of substantial length, the loops of the strands being arranged oppositely and the reaches of the strands between the loops being xedly secured together, the end arms of the terminal loops being disposed parallel to one another and terminating in laterally disposed lugs facilitating the attachment of the arms to a supporting element, said end arms being substantially spaced from one another when relaxed, said arms being denected toward one another and the lugs attached to said supporting element,*whereby to tension said terminal loops. l

5. A spring unit comprising load supporting strands of spring wire arched medially in the direction of the load, and means rigidly and abuttingly supporting said springs at the ends thereof and restraining the same from endwise movement, said strands being subject to compressive stress only under load and maintaining the bow thereof in said direction under all normal loads, the strands having longitudinally spaced open, U-shaped loops therein of substantial length, the loops of the respective strands being arranged oppositely and the reaches of the strands between the loops being twisted together to rigidly bind the strands in mutually bracing relationship resistant to relative movement of said reaches under compressive flexing of said strands, said strands acting as a unit to resist twisting, said means restraininglyengaging the strands to prevent rotation about the axis thereof and the strands acting as a unit to resist twisting about said axis when so restrained.

6. A spring unit comprising load supporting strands of spring wire having a bowed set in the direction of the load, and means rigidly and abuttingly engaging said springs at the ends thereof and restraining the same from endwise movement, said strands being subject to compressive stress only under load and maintaining the bow thereof in said direction under all normal loads, said strands having oppositely disposed open, U-shaped loops therein of substantial length and being connected between said loops in rigid mutually bracing relationship resistant to lateral or longitudinal spreading movement between said loops under compressive exing ofl the strands, said means engaging said strand ends to prevent rotation of the strands about the axis thereof and the strands acting as a unit to resist twisting about said axis when so restrained rotatively.

THEODORE D. STEWART. WILLIAM A. CLARK. 

